Items in AFP with MESH term: Anesthesia, Local
ABSTRACT: The use of effective analgesia is vital for any office procedure in which pain may be inflicted. The ideal anesthetic achieves 100 percent analgesia in a short period of time, works on intact or nonintact skin without systemic side effects, and invokes neither pain nor toxicity. Because no single agent meets all of these criteria, the physician must choose from the available armamentarium based on the anesthetic properties that are most desired. Infiltrative anesthetics are frequently chosen because of their proven safety record, low cost, ease of storage, widespread availability, and rapid onset of action. Allergy to local injectable anesthetics is rare, and when it occurs it is often secondary to the preservative in multidose vials. Anesthesia can be prolonged with the addition of epinephrine or the use of longer-acting agents. Buffering the local anesthetic with bicarbonate, warming the solution, and injecting slowly can minimize the pain of anesthetic injection. Complications are rare but include central nervous system and cardiovascular toxicity, or extreme vasoconstriction in an end organ, if epinephrine is used.
ABSTRACT: The development of topical anesthetics has provided the family physician with multiple options in anesthetizing open and intact skin. The combination of tetracaine, adrenaline (epinephrine), and cocaine, better known as TAC, was the first topical agent available for analgesia of lacerations to the face and scalp. Cocaine has been replaced with lidocaine in a newer formulation called LET (lidocaine, epinephrine, and tetracaine). For analgesia to nonintact skin, LET gel is generally preferred over TAC because of its superior safety record and cost-effectiveness. EMLA (eutectic mixture of local anesthetics) is perhaps the most well-known topical anesthetic for use on intact skin. EMLA can be used to anesthetize the skin before intramuscular injections, venipuncture, and simple skin procedures such as curettage or biopsy. To be fully effective, EMLA should be applied at least 90 minutes before the procedure. ELA-Max is a new, rapidly acting topical agent for intact skin that works by way of a liposomal delivery system and is available over the counter. Other delivery vehicles for topical anesthesia currently in development, including iontophoresis and anesthetic patches, may one day give patients and physicians even more flexibility.